Insectproofing wool with zinc acetate

ABSTRACT

Wool is reacted with zinc acetate in the presence of a polar, high-boiling solvent, yielding a modified wool which has increased resistance to insects.

ted States Patent Koenig et al.

[ Dec. 23, 1975 INSECTPROOFING WOOL WITH ZINC ACETATE Inventors: Nathan H. Koenig, Albany; Mendel Friedman, Moraga, both of Calif.

The United States of America as represented by the Secretary of Agriculture, Washington, DC.

Filed: Sept. 24, 1973 Appl. No.: 399,873

Assignee:

References Cited UNITED STATES PATENTS 8/1933 Jones 424/289 Spearman 8/128 Koenig 8/128 Koenig 8/128 Koenig 8/128 Koenig et a1 8/128 R Primary Examiner-Theodore Morris Attorney, Agent, or FirmM. Howard Silverstein; W.

Takacs ABSTRACT Wool is reacted with zinc acetate in the presence of a polar, high-boiling solvent, yielding a modified wool which has increased resistance to insects.

4 Claims, No Drawings INSECTPROOFING WOOL WITH ZINC ACETATE A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is

hereby granted to the Government of the United States of America.

DESCRIPTION OF THE INVENTION This invention relates to and has among its objects the provision of novel processes for modifying wool in order to increase its resistance to insects. Further objects of the invention will be evident from the following description wherein parts and percentages are by weight unless otherwise specified.

Although wool is a very useful fiber, it is subject to attack and destruction by insects, particularly moths and carpet beetles. Various treatments are available to protect wool from insect attack. Unfortunately, the known treatments suffer from such disadvantages as being cumbersome, time-consuming, non-durable, toxic, costly, or combinations of these.

The invention described herein provides a means for obviating the problems outlined above. In accordance with the invention, wool is reacted with zinc acetate in the presence of a special solvent, whereby there is formed a modified wool which exhibits increased resistance to insect attack.

A primary advantage of the invention is that it yields modified wool which is more resistant to insect attack than normal wool. Moreover, insect resistance is attained rapidly by a simple process. A further advantage of the invention is that the treatment is inexpensive.

Another advantage of the invention is that the improvement is essentially permanent. The treated wool does not lose its insect resistance after long use or repeated dry cleaning, but retains these properties for the life of the material.

A further advantage of the invention is that the modified wool retains its intrinsic properties so that it is useful for all the conventional applications as in fabricating garments, blankets, rugs, etc.

DETAILED DESCRIPTION OF THE INVENTION In the process of the invention, wool is reacted with zinc acetate in the presence of a special polar, highboiling solvent, namely, N,N-dimethylformamide (hereinafter referred to as DMF), N-methyl-2-pyrolidinone, dimethyl sulfoxide, or ethylene glycol. The amount of solvent may be varied from about 1 to 20 parts thereof per part of wool. Generally, 4-8 parts of solvent per part of wool is sufficient and provides good results.

The amount of zinc acetate used in the reaction may be varied, depending on the degree of modification desired. Usually one uses about 0.2 to 3 parts thereof per part of wool.

The reaction is carried out at a temperature from 25 to 135C. The rate of reaction increases with temperature, and it is preferred to conduct the reaction at 105-l 20C., whereby to achieve a rapid result without damage to the wool. The wool may be dry, or it may contain its natural moisture content, i.e., about 10-15%.

The time of reaction will depend on such factors as the solvent selected, the amount of zinc acetate, the temperature of reaction, and the degree of modification desired. Thus the reaction may take anywhere from a few minutes to several hours. Usually, the reaction is continued for a time necessary to provide a weight increase (by the wool) of about 5-20%, preferably 10-15%.

After reaction of the wool with zinc acetate, the chemically-modified wool is preferably treated to remove unreacted zinc acetate. Thus the wool may be treated as by wringing, passage through squeeze rolls, centrifugation, etc., to remove the excess reagent. In place of such mechanical treatment, or in conjunction therewith, the modified wool may be extracted with an inert volatile solvent such as butanone, trichloroethylene, alcohol, and the like. Preferably, the extraction solvent is heated prior to use to facilitate removal of excess reactant. Successive extractions with different solvents may be used to ensure complete removal of all unreacted material. The treated wool is then dried in the usual manner. 1

Although the properties of the products of the invention indicate actual chemical combination of the wool with the zinc acetate (or at least the zinc moiety thereof) has taken place, it is not certain that this is the mechanism involved. It is believed that the zinc moiety reacts with the amino, imidazole, guanidino, hydroxyl, phenolic, and carboxyl groups of the wool, including cross-linking reactions. It may be, however, that other reactions occur and it is not intended to limit the invention to any theoretical basis.

It is to be noted that the reaction in accordance with the invention does not impair the wool fiber for its intended purpose, that is, for producing woven or knitted textiles, garments, etc. The process of the invention may be applied to wool in the form of fibers, as such, or in the form of threads, yarns, slivers, rovings, knitted or woven goods, felts, etc. The wool textiles may be white or dyed goods and may be of all-wool composition or blends of wool with other textilefibers such as cotton, regenerated cellulose, viscose, animal hair, etc.

EXAMPLES The invention is further demonstrated by the following illustrative examples.

The wool used in the experiments set forth below was scoured, undyed wool, exhaustively extracted with trichloroethylene followed by ethanol, then dried for 70 minutes at 120C. All weightincreases are given on a dry wool basis. Zinc acetate was in the form of the dihydrate, Zn(C H -,O .2I-I O.

EXAMPLE 1 A circular sample (8.0 cm.) of dried wool fabric (1.2 g.), zinc acetate (0.20 g.), and DMF (6 ml.) were placed in a covered (but unsealed) Petri dish and held in an oven at 110C. for 45 minutes. The treated wool sample was successively extracted with warm butanone and overnight with hot ethanol to remove unreacted material. The sample was then dried for 70 minutes at Zinc acetate, g. Weight increase,

I -continu ed Zinc acetate, g. Weight increase,

EXAMPLE 2 A sample of dry wool fabric (1.2 g.), zinc acetate (1.5 g.), and DMF (6 ml.) were heated in a Petri dish at 110C. at times tabulated below. The treated wool sample was extracted and dried as in Example 1.

The above procedure was repeated substituting either zinc chloride or zinc bromide.

The increase in dry weight of all samples is summarized below. The special value of zinc acetate is shown by the higher weight increase of the wool compared to zinc chloride and zinc bromide.

Weight increase,

Salt 45 min. 90 min.

Zinc acetate 13 13 Zinc chloride 5 5 Zinc bromide 5 6 EXAMPLE 3 Solvent Weight increase,

N-Methyl-Z-pyrrolidinone 17 Dimethyl sulfoxide l2 Ethylene glycol 16 EXAMPLE 4 A swatch (24 X 14 cm.) of dried wool fabric (7.0 g.), zinc acetate (16.0 g.), and DMF (50 ml.) were placed in a 25 X 14 cm. pan. The pan was covered with a glass plate and held in an oven at 1 10C. for 60 minutes. The treated wool sample was extracted and dried as in Example l. The increase in dry weight of the wool was 15%. This product was tested as follows:

lnsect resistance was tested on treated and untreated wool replicate fabric samples (0.5 g.) by exposing them to larvae of the black carpet beetle for 14 days. The average excrement weight from each sample was then measured. The results as tabulated below show the greatly increased insect resistance conferred by the treatment. The marked reduction of excrement with treated wool reflects the protection by the treatment against larval attack.

Having thus described our invention, we claim:

1. A process for preparing modified wool which has increased resistance to insects, which comprises reacting wool with zinc acetate in the presence of N,N-dimethylformamide at a temperature of about from to C. until there is attained a weight increase by the wool of about from 5 to 20%. I

2. A process for preparing modified wool which has increased resistance to insects, which comprises reacting wool with zinc acetate in the presence of N-methyl- 2-pyrr01idinone at a temperature of about from 105 to 120 C. until there is attained a weight increase by the wool of about from 5 to 20%.

3. A process for preparing modified wool which has increased resistance to insects, which comprises reacting. wool with zinc acetate in the presence of dimethyl sulfoxide at a temperature of about from 105 to 120 C. until there is attained a weight increase by the wool of about from 5 to 20%. p

4. A process for preparing modified wool which has increased resistance to insects, which comprises reacting wool with zinc acetate in the presence of ethylene glycol at a temperature of about from 105 to 120 C. until there is attained a weight increase by the wool of about from 5 to 20%. 

1. A PROCESS FOR PREPARING MODIFIED WOOL WHICH HAS INCREASED RESISTANCE TO INSECTS, WHICH COMPRISES REACTING WOOL WITH ZINC ACETATE IN THE PRESENCE OF N,N-DIMETHYLFORMAMIDE AT A TEMPERATURE OF ABOUT FROM 105* TO 120*C. UNTIL THERE IS ATTAINED A WEIGHT INCREASE BY THE WOOL OF ABOUT FROM 5 TO 20%.
 2. A process for preparing modified wool which has increased resistance to insects, which comprises reacting wool with zinc acetate in the presence of N-methyl-2-pyrrolidinone at a temperature of about from 105* to 120* C. until there is attained a weight increase by the wool of about from 5 to 20%.
 3. A process for preparing modified wool which has increased resistance to insects, which comprises reacting wool with zinc acetate in the presence of dimethyl sulfoxide at a temperature of about from 105* to 120* C. until there is attained a weight increase by the wool of about from 5 to 20%.
 4. A process for preparing modified wool which has increased resistance to insects, which comprises reacting wool with zinc acetate in the presence of ethylene glycol at a temperature of about from 105* to 120* C. until there is attained a weight increase by the wool of about from 5 to 20%. 